In her first novel, The Song of Achilles, Madeline Miller retold the siege of Troy from the point of view of Patroclus, whose death Achilles avenged by unleashing outsize destruction on Troy and especially on Hector, whose body he tied to his chariot and dragged around the city walls. Homer did not spell out the exact nature of a relationship that might trigger such a reaction; Miller made it a love story, tender and loyal, and by clearly showing what Achilles’ hubris would cost him gave it not only intimacy but the arc of true tragedy. The Song of Achilles now exists in 23 languages and despite disapproving mutterings in some quarters – it had “the head of a young adult novel, the body of The Iliad and the hindquarters of Barbara Cartland”, according to the New York Times – won what was then still called the Orange prize.

A striking aspect of The Song of Achilles was the degree to which Miller was alive to gendered inequalities of power, describing how fighting men gathered when a well-born woman (Helen) came to puberty, and how Greek wars were fought: arrive, kill the men, take the women, parcel them out, tumble them on marsh-reed beds then require them to serve and feed the now entrenched army. This could be seen especially in her characterisation of Thetis, a young nymph given by the gods to the mortal Peleus. A kind man who would become a well-loved king, Peleus was nevertheless required, by those same gods, to overpower her; the rape resulted in Achilles, “best of the Greeks” – and made the nymph as chilly and harsh toward humans as the depths of the sea in which she lived.

Circe, the subject of her second book, is also a nymph. “Brides, nymphs were called, but that is not really how the world saw us. We were an endless feast laid out upon a table, beautiful and renewing. And so very bad at getting away.” Daughter of a naiad and Helios the sun god, Circe is immortal, and this first-person account is a kind of greatest hits of the ancient Greek world: Prometheus and his endless punishment, Scylla and Charybdis, Hermes, Apollo, Athena, Daedalus and his son Icarus, Ariadne and the Minotaur (who is Circe’s nephew), Jason and the Golden Fleece – and Odysseus, of course, who in Book 10 of The Odyssey encounters Circe when he lands on her island and she changes some of his sailors into pigs. As so often, the gods are portrayed as vain and retribution-minded; born bursting with “excellences”, as Miller’s Circe puts it, “they find their fame by proving what they can mar: destroying cities, starting wars, breeding plagues and monsters”. If this was all there was (and at the beginning of the novel, it is all it feels there is going to be), Miller would be dealing with a problem familiar from magic realism: if literally anything can happen, if there is always some new monster or god with new powers then why care about any of it? But Miller also knows that, as with the best magical realism, the real power doesn’t lie in the ostensible facts of the narrative, but in its psychology.

And that is where Miller anchors her story – in the emotional life of a woman. She is not the first to see the potential in Circe, who over the centuries has been interpreted as everything from a parable against drunkenness to an embodiment of emasculation. From the moment Circe realises, as a young girl, that she is scorned for her ungainliness, to her rebellion against her family with a good-looking ne’er-do–well; from her self-harming rages to the joys and lonelinesses of independence; from finding a vocation to the challenges of single motherhood (even goddesses, in this telling, can run out of nappies), Miller’s is a feminist version in which everything is at stake. In this context, turning ravening sailors into pigs is not just another hurdle for all-conquering Odysseus to overcome, but necessary self-defence.

What is gained by Circe’s immortality is, in the main, what is gained in any long life if you are willing to look past yourself. Circe learns the importance of balancing trust and self-protection. We learn that Jason may be beautiful and strong, but he is also “lost in the details of his own legend”; that Hermes is all very well as a lover, as long as one doesn’t ever commit the sin of being dull; that Odysseus is “lawyer and bard and crossroads charlatan at once” – who nevertheless is also capable of real grownup care. “He showed me his scars and in return let me pretend that I had none.” We discover that even gods would improve by experiencing “guilt and shame, remorse, ambivalence” – which are other ways of saying self-knowledge – but most never do. That magic is greater than deity, because magic is made of humble materials, and work and will; no amount of godhead will make up for practice, and no amount of power replace a steady love.

It is out of these insights, sprung as surprises that often contain within them a retrospective inevitability, that Miller achieves real narrative propulsion. Some will consider her prose too purple, her plotting too neat, but others will find it supple, pitched in a register that bridges man and myth. At one point, Odysseus’s mind is described as being like “the spiral shell. Always another curve out of sight”. Miller has taken the familiar materials of character, and wrought some satisfying turns of her own.

• Circe by Madeline Miller (Bloomsbury Publishing, £16.99). To order a copy for £12.99, go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min. p&p of £1.99.